Rock drill



@ct E9 1926.

W. A. SMITH ROCK DRILL Filed Sept. 13. 1924 F n. /@Q

HIS ATT NEY 'Patented @etl lg, i926.

metaal V/'LLIA-MFA. SMT-, 0F ATHENS, PEENSYLVANA., ASSIGNOR TO ING-ERSOLL-*RAND GGFIPANY,' OF JERSEY CITY,

NEW JERSEY, .A CORPORATION OF NEW JERSEY.

. l ROCK DRILL.

Applieationiled September 13, 1924. Serial No. 737,510.

This invention relates to a fluid actuated y rock drill, preferably of the hammer type having the free exhaust controlled by the piston and valve controlled Vinlets for the cylinder.

The objects of the invention are to improve upon the type Vof inlet valve employed in such machines and to obtain a more di rect communication between the supply of live motive fluid at both ends of the cylinder than heretofore by means of a light, strong, durable valve preferably of plate form capable of quick and positive movement in unison with the piston and free from the troubles of fluttering and centering during operation.

The preferred embodiment of the invention by which these objects are accomplished comprises a fiat plate tapered from the center toward the ends and adapted to oscillate with low lift on a flat valve seat provided with ports leading to the ends of the cylinders. Preferably the valve is substantially as long as the stroke of the piston so that the ports are short. The short ports thus provided permit quick admission of the live motive fluid to the cylinder and reduce clearance in the cylinder to a minimum which makes for quick response of both piston and valve to the movements of each other. Certain mechanical advantages are found in this construction. rlhe valve seat being` is easily machined and lground and the faces of the valve being flat and rectangular make the valve easily manufactured. ln addition to these advantages of operation and manufacture, the valve chest or box is relatively flat, lying close to the cylinder occupying relatively little room. Also the valve chest and valve are light in weightand therefore are a relatively small part of the vtot-al weight of the machine.

The invention will be more clearly understood by referring to the following description and the accompanying' drawing which illustrates one embodiment which the invention may assume in practice.

Figure l is a longitudinal sectional view of a rock drill of the hammer type provided with inlet ports for the admission of live motive fluid controlled by a plate valve constructed in accordance with the practice of the invention,

Figure 2 is a section through the valve box showing in plan more particularly the y arrangement of the plate valve and the inletports and compression relief valve which the flat valve controls, and

Figure 3 is a perspective view of one of the compression relief valves. Referring to the drawing the rock drill illustrated isof the hammer type being provided with a cylinder A within Which la hammer piston BV is adapted to reciprocate. rlhe rear of the cylinder is closed by means of a back head C and a back cylinder Washer D, between which the ratchet mech? anism E is inclosed cooperating with a ratchet `ring F to produce rotation of the piston and the drill steel. The rock-drill is of the free exhaust type having aI free exhaust port G controlled by the piston B. The forward` end of the cylinder A. is closed by a front cylinder washer H cooperating with the nose J of the piston B.

The piston B is actuated by admitting live motive fluid such as compressed air alternately to the opposite faces of the piston B through ports K and L at the front and rear end respectively of the cylinder A. These ports extend directly into a long low valve chest comprising aflat seat O, a spacer P in this instance having an elongated rectangular op'enng forming a valve chamber, and an inclosing cover Q, .whichl is adapted to house a suitable throttle valve R for controlling the supply of livemotive fluid yfrom a suitable pipe connection S through a passageway T into the valve chamber Within the valve box.

rlhe valve U for controlling the flow of live motivefluid from the valve chamber to the ports K and'L comprises a long thin piece of material substantially as long as the stroke of the piston plus the length'of'the piston head B and fitting the valve chamber substantially closely vand having only slight clearancev except at the ends of the valve as shown in Figure 2, there beino` left a substantial clearance as shown at Vband W at the opposite ends of the valve chamber to permit the live motive fluid to pass over the valve ends and thence into the ports l and L. The amount of clearance allowed is preferably such that the area of the pas-v over the-ends of the valve to cause a drag on tlievalve and close the valves When'the pressure beneath the valve is reduced.

rIhe valve U is tapered uniformly from the center toward each end and is adapted to rock or oscillate on the seat O about the center of the valve as a pivot. The center of the valve forms a fulcrum bearing directly on the bottom of the valve chest. Means are provided to center the valve U including a pin X held in place in a boss Y 'formed on the inner side ofthe cover Q, the pin `being adapted to extend ydownwardly into an aperture Z in the valve U and thus lies transverse to the axis of oscillation of the valve. Preferably the spacer P is of substantially the saine thickness as the thickest portion of the valve U at its center. The face of the boss Y being in plane of the upperspacer I holds the center of the 4valve U from leaving thevalve seat O for anyappreciable distance When the drill is turned on its side or upside down. In operation the valve always lies directly on the bottoni of the valve chest or valve chest seat. I have shoxvnthe valve ofrectangular shape as one preferred form of the invention and in this form, it Will be understood that the valve is broad compared to its length and `thus has very considerable Width in order to 'form broad flat surfaces at top and bottoni to produce pressure areas.

As the piston B i'eciprocates and passes the center exhaust port (i some of the motive fluid is apt to be trapped in front or ahead of the piston causing' compression which would tend to reduce the force of the piston blow.

b and c intermediate the inlet poi'ts K and L respectively and the free exhaust port Gr. The relief ports Z) and 0 are controlled by valves d and e respectively independent of the valve Il and are in turn controlled by the fluid pressure on the underside of the valve U. The compression relief valves Zand e are preferably round and flat and iit in chambers f and at the underface of the valve seat O. These chambers and g as shown communicate with the cha ber c leading to the free exhaust port G. The ports /i and j leading from the chambers f and g respectively through the valve seat cause the valves d2 and c to be subjected to the ressuie at the under side of the ralve U. I`hus, when the valve U lies fiat on the face of the seat O, the pressure on one of the relief valves (l and e is very slight. The compressed fluid from the cylinder A is adapted to escape through one or the other of the relief ports and c into the chamber 7u which communicates vwith the free exhaust port Gr, as shown by the dotted lines.

In operation, live pressure fluid on top of `the valve U at the end open to free exhaust noi-t o i through which port the exhaust passes un-` Meansare provided to relieve the compression in the cylinder A through ports through the port G holds thevalverU down y' into the cylinder behind the piston B. In `Figure l the piston B is starting forward and the air isibeiiig exhausted in front of the piston until the free exhaust Gr is closed, tlieieafte compression in front of the piston prevented by the compression relief 7 maintained open by the valve d,

tii closed by the piston. As the compression relief port 5 is closed by the piston, the tree exhaust port G begins to open behind the piston which causes a drop in pressure in the rearward end of the cylinder and underneath the broad 'fiat surface extending from the center to the end of the valve U so that the rush of pressure fluid over the end of the valve U to the exhaust port G rocirs the valve and opens the inlet K to the forward end of the cylinder. At the seine time, 'the ive air on top of the forward compression relief valve d closes said vire, rlhe large extent of the area underneath 'the valve U due to the length and and the drop in pressure thereunder which takes place enables the live air on top of the valve U to actuate it causing the closingV "lares of 'the valve and the cooperating surface of th valve seat due to the machining,

`live pressure 'liuid ie'iay leali over the edges of the seated left hand ving of the valve,V shown in Figui-c I5 and enter between theV valve and its seat, so that this Wing is nearly balanced f and only slightly iinbaluiiced. The valve is thus readily rocked by the rush of fluid over the opposite ror right hand end of the vaive as Figure l is viewed,

and througggh the restricted lift area of theV valve formed betr-keen the valve surface and the inlet port, aided by the pressure due to live pressure fluid on top of the right hand end of the valve, When the reduction of pressure occurs underneath the said right f .hand end of the valve, and this cycle is repeated when the valve is rocked in the opposite 'direction The valve thus operates regardless lof the compression or lack of compression at one end or the other.

A material advantage which is possessed by a tool constructed in accordance with this invention is the fact that the valve U does sion is not a reliable factor since its valueis effected by wear, speed of operation and other elements. @ne important factor ef fecting the operation of the present valve is the tightness with which the valve seats over the ports on the valve seat O, and this has been found to improve with use because the valve U as it wears will seat tighter with use and wear to a sustaining seat over the ports.

The drill illustrated isl of the rifle bar rotation type, the rifle bar 0 being Aformed integrally with the ratchet mechanism E and cooperating with a nut p to rotate the piston B. The tinted nose J of the piston engages a chuck bushing g which is casteh lated at its end to engage the chuck r. A lug steel s is adapted to be gripped by a sleeve t mounted in the chuck r and rotated thereby. rhe chuck r is adapted tobe housed within the front head a which may be attached in any suitable manner to the forward extension n of the cylinder A. l-Vater for cleansing the hole being drilled is supplied through a Water tube w extendinglongitudinally through the piston B into the hollow bore of the steel s from the back head C at which suitable water connections (not shown) may be made.

This inngroved valve is of the current thrown type dependent for operation upon a free exhaust controlled by the'piston, in contra-distinction to a valve of the compression thrown type or a valve of the balanced wing type, in which latter type one wingv controls the inlet port-s and the other wing controls the exhaust ports. My valve has great length and has substantially great width or breadth comparedto its length, so that the valve has broad flat surfaces extending from the center of "oscillation outwardly. The ends or wings of the valve are imperforate, and as the valve oscillates on a fulcrum bearing directly on the bottom of the valve chest, provision is afforded for the maximum effect on the valve of the drop of pressure as it occurs in one end or the other of the. cylinder, due to the opening of the piston controlled exhaust port. rthe valve fits substantially closely along the sides of the valve chest, so that there is a substantial differential between the presL eures on the top and bottom of one end of the valve when the drop in pressure occurs underneath one end, to enable the valve to be actuated or oscillated by the rush of fluid over the end of the valve. For these reasons, the drop in pressure through an open inlet port beneath the broad and relatively large surface area of a valve wing, due to the opening of the free exhaust port, and the consequent momentary increased flow of pressure fluid over the end of the valve, will causethe valve to oscillate.

l claim:

l. A fluid actuated rock drill, comprising a cylinder and reciprocating piston, a free exhaust port in the cylinder controlled by the piston, a valve chest having a flat seat, inlet ports for the ends of the cylinder leading from' the ends ofthe valve chest seat, and an oscillating plate valve in said valve chest, consisting of a long, thin, flat piece of metal having substantial breadth and low lift compared to its length, in order to con stitute broad flat imper and comparatively low and restricted lift areas between the faces of the valve and the inlet ports, the ends of the valve controlling` the inlet ports, and the side edges of the valve fitting the sides of the valve chest substantially closely with slight clearance, the pressure of live pressure fluid on top of that wing of the valve which momentarily lies fiat upon the valve seat being nearly balanced by leakage of live pressure fiuid over the edges of the said valve Wing and underneath the surface of the wing, whereby the drop in pressure underneath the lifted wing of the valve, due to the opening of the free exhaust port, will create a momentary increased flow of pressure fluid over the end of the valve and through the restricted lift area at that end, and will cause the valve to oscillate, aided by the live pressure fluid on top of the said lifted valve wing.

2. A fluid actuated rock drill, comprising a cylinder and reciprocating piston, a free exhaust port in the cylinder controlled by the piston, a valve chest having a flat seat, inlet ports for the ends of the cylinder leading from the ends of the valve chest seat, and an oscillating plate valve in said valve chest, consisting of a long, thin, flat piece of metal having` substantial breadth and low lift compared to its length, in order to constitue broad flat imperforate wing surfaces and comparatively low and restricted lift areas between the faces of the valve and the inlet ports, the ends of the valve controlling the inlet ports, and the side edges of the valve fitting` the sides of the valve chest substantially7 closely with slight clearance, the pressure of live pressure fluid on top of that wing of the valve which momentarily lies flat upon the valve seat being nearly balanced by leakage of live pressure fluid over the edges of the said valve Wing and underneath the surface of the wing, the slight clearance at the sides of the valve causing the live pressure fluid to flow over the end of the opposite lifted wing and the restriction of the lift area producing an inital drop in pressure under the valve at that end, but

orate wing surfaces insufficient to cause the valve to oseillate, whereby the drop in pressure underneath the lifted wing of the vulve due to the opening of the free exhaust port, will create a m0- mentary increased How of pressure Huid over the end of the valve and through the restricted lift area at that'end, and will cause the 'valve to oscillate, ladded by the live pressure fluid on top of the said lift-ed valve Wmv.

IiiJ testimony whereof I have signed this specification.

WILLIAM A. SMITH. 

